<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8" />
    <title></title>
  </head>
  <body>
    <div id="app">
      <div :style="{ color: activeColor, fontSize: fontSize + 'px' }">
        1111111111
      </div>
      <div :style="{ 'font-size': fontSize + 'px' }">2222222222</div>
      <div :style="styleObject">3333333333</div>
    </div>

    <script src="https://unpkg.com/vue@3/dist/vue.global.js"></script>
    <script>
      const { createApp, ref, reactive } = Vue;

      createApp({
        setup() {
          const activeColor = ref("red");
          const fontSize = ref(30);

          const styleObject = reactive({
            color: "red",
            fontSize: "13px",
          });

          return {
            activeColor,
            fontSize,
            styleObject,
          };
        },
      }).mount("#app");
    </script>
  </body>
</html>
